If you've been inactive all of this time--- then any amount of exercise will be beneficial (and good for you!). I do like some exercise dvd's and you can get them at your library or 'on demand' if you have cable. Or you could buy some from ebay. Even just put on music and just dance around the house.
You mentioned what is my absolute biggest motivation---- kids! I want to stay healthy in order to be with them for as long as possible. I also want to model physical fittness for them so that they grow up to want active lives as well.
good luck-- take it slow in the begining!
Try something fun, like Wii games and fitness. I have lost 3lbs already in 1 week doing Wii sports and Zumba 2. It is fun and u can include ur family.
I assume u mean motivation am I right ?
Motivation is from determination and that leads to success
Motivate urself by saying positive things to yourself or to your daughter such as have a great day or mommy's so proud of u